Concrete engravers for making decorative grooved patterns in the surface of hardened or cured concrete, pavement, or the like are known in the art. Notable among these is an earlier teaching by Adamson in U.S. Pat. No. 5,176,426, the disclosure of which is herein incorporated by reference. The apparatus of U.S. Pat. No. 5,176,426 is generally useful for making grooves referred to as "transverse" grooves (for which a small cart that carries the cutting wheel is guided along the groove path by a tracking arrangement portion of the apparatus) and for making grooves referred to as "longitudinal", for which the cart is held stationary and a cutter carriage moves relative to the cart in order both to translate the cutting wheel along the longitudinal groove path, and to move it vertically between a preset cutting position and a higher elevation at which the cutter does not engage the concrete.
The concrete engraver taught in U.S. Pat. No. 5,176,426 includes a body with a perimeter frame used to limit the cutting depth of one of two mutually perpendicular circular cutting wheels. The perimeter frame includes aligned linear cams, i.e., raised attachments to the frame. The longitudinal-groove cutter is mounted in a carriage on two linear guide shafts and uses a rotatable cam follower in the process of making a longitudinal groove. When this is done, the cam follower rolls down a lead-in ramp, traverses a portion of the frame and then either stops or rolls up a second ramp and thereby makes a groove of predetermined length and depth. The maximum length of the longitudinal cut is limited by the length of that part of the frame that is between the lead-in ramps of the linear cams.